The prevalence of glucose intolerance was determined in a sample of 192 adults (34% of the adult population) from Wanigela in rural Central Province, Papua New Guinea. This centre was chosen to compare the high prevalence rates previously found in residents from this village who had become urbanized in Port Moresby. The age- and sex-standardised rates for abnormal glucose tolerance in Wanigela were significantly lower than those recorded in the urban community. However, the crude rates of 8.9% for diabetes and 5.7% for impaired glucose tolerance are among the highest reported for rural populations in the Pacific. These results strongly suggest that a genetic predisposition to glucose intolerance is present in this ethnic group, and argue for the early adoption of primary prevention programmes as the process of development encroaches rapidly upon the traditional lifestyles of previously isolated communities in Papua New Guinea.